Siemens RL Instructions

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FUSE FUNCTIONS
CURRENT LIMITING FUSES
Current limiting (C.L.) fuses are used to increase the inter-
ruption capacity beyond that of the breaker alone or to the
limit the fault "let-thru" current down stream of their instal-
lation. The C.L. fuses used with the RL series of circuit
breakers are special purpose fuses having NEMA Class
"J" or Class "L" characteristics with a 200,000 Amps RMS
Symmetrical interrupting capacity.
When fuse replacement is required, only use fuses per
Siemens-Allis drawing 71-142-200 with the same rating as
supplied with the circuit breaker. Different fuses may not
properly mount on the breaker and may have different
protective characteristics.
The current limiting fuses for the larger frame sizes, RLF-
3200 and RLF-4000 mount on a separate fuse draw-out
assembly, covered in detail in instruction book SG-3078 .
OPEN FUSE TRIP DEVICE
A
DANGER
~
HAZARDOUS VOLTAGE
Do not remove trigger fuse cover when circuit
breaker is in CONNECT position. Line voltage
may be available inside trigger fuse assembly.
Failure to observe these precautions could result
in property damage, electrical shock, burns.
serious personal injury or death.
The Open Fuse Trip mechanism has three functions. First.
to trip the circuit breaker mechanically when a C.L. fuse
has
interrupted.
Second, to indicate which phase C.L. fuse has interrupted.
The plunger on top of the trigger fuse ( 12). indicates visu-
ally which phase C.L. fuse has interrupted .
Third. to retain the breaker in the trip-free position until
the trigger fuse is replaced.
Page 17
Each trigger fuse is wired in parallel with one of the C.L.
fuses. When the C.L. fuse interrupts. its associated trigger
fuse also opens and releases a plunger which releases a
precompressed spring contained in the trigger fuse hous-
ing. On the small breakers, this plunger operates arm (6)
which moves the latch (11 ), releasing the spring-loaded
lever (3). This engages circuit breaker trip flap link (7).
This trips the circuit breaker and holds the circuit breaker
in the mechanical trip-free position.
On the circuit breakers supplied with a separate fuse car-
riage the trigger fuses are mounted on the fuse carriage,
and are used for visual identification of the faulted phase.
Tripping of the breaker is accomplished through a power
supply connected across the main fuses of the fuse car-
riage, the voltage from this supply is applied through the
secondary control wiring to the coil of a solenoid mounted
open fuse trip device on the circuit breaker. The plunger of
the solenoid operates arm (6). The balance of the opera-
tion is the same as for the trigger fuse operated device.
The circuit breaker will remain trip free (cannot be closed)
unti I the trigger fuse has been replaced and the associated
trip mechanism reset lever (3), has been manually reset
(pushed up).
illili@\j Do not remove trigger fuse cover when
breaker is in connected position. Line
voltage may be available inside the trig-
ger fuse assembly.
To remove the trigger fuse, remove screw (15) remove
plastic cover (5) then the trigger fuse.
To insert the trigger fuse. reverse the above procedure.
[§11:~\J!i~IN.: The trigger fuse (13) must be inserted
· · ··· with the plunger facing arm (6). The gap
dimension of 0-.03" (0.8 mm) maximum
must be maintained for each fuse. Be
sure
to replace both the trigger fuse and
its corresponding C.L. fuse before the
breaker is reset
Courtesy of NationalSwitchgear.com

Siemens RL Specifications

General

Rated Voltage	250VAC, 30VDC
Mechanical Life	10, 000, 000 operations
Operating Temperature Range	-40°C to +70°C
Contact Configuration	SPDT
Contact Rating	10A
Electrical Life	100, 000 operations
Mounting Type	PCB